Electric switch



June 21, 1960 G. J. MEUER 2,942,087

ELECTRIC SWITCH Filed March 29, 1957 2 Sheets-Sheet 1 Er -5 i; 6a

@mnbv 53 221 June 21, 1960 G. J. MEUER 2,942,087

ELECTRIC SWITCH Filed March 29, 1957 2 Sheets-Sheet 2 a4 a5 C M 80 6M 6 G -55 gbxwvy ggkwr v United States Patent() ELECTRIC SWITCH George J. Meuer, Milwaukee, Wis, assignmto Cutler- Hammer, Inc., Milwaukee, Wis, a corporation of Delaware Filed Mar. 29, 1957, Ser. No. 649,456 8 Claims (Cl. 200-157 'This invention relates generally to electric switches.

More Specifically the invention relates to switch operating mechanisms. While the invention disclosed herein is embodied in a manually operated trigger type switch adapted for use in portable electric tools, it is to be understood that its use is not so limited.

It is an object of the invention to provide novel operating mechanisms for electric switches."

. Another object is to provide switches employing such electrical contact is established and broken in positive fashion.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodime'nts'of the invention which will now be described, it being understood that the embodiments illustrated are susceptible of modifications with respect to certain structural details thereof without departing from the scope of the appended claims.

. .In "the drawings:

Fig. 1 is a side elevation of a trigger switch incorporating the invention shown within the handle of an electrical devicesuch as a portable tool;

Fig. 2 is an. end elevation of said switch and handle;

Fig. 3 is a top plan view of said switch;

Fig. 4 is a bottom plan view of said switch;

Fig. 5 is a top plan view of the base portion of said switch with certain members removed to shown details;

Fig. 6. is a sectional view of said switch showing it in. open position; the upper portion of the section,

specifically the trigger lever, frame, contact carrier and both insulator plates, is taken along line 6a-6a of Fig. 3; the lower portion of the section, specifically the base member, is taken substantially. along line 6b6b of Fig. 5;

Fig. 7 is a top plan view of the trigger lever member of said switch;

.Fig. 8 is a sectional view of said switch similar to that shown in Fig. '6 but showing said switch in closed position;

.'Fig. 9 is a detail view of a bussing clip carried within the base of said switch;

Fig. 10 is a detail view of one of two contact clips carried within the base of said switch;

Fig. 11 is a detail view of the bridge contact member employed in said switch;

Fig. 12 is a top plan view of an alternative form of base member foruse with said switch;

f Fig. 13 is a sectional view of said alternative form of base member taken along line 13 -13 of Fig. 12;

. the floor of the chamber.

Fig. 1.4 is aneleuational view of a side of an alternative form of frame member that may be used with said switch; and

..Fig. 15 is a detail view of an alternative form of bussing clip which is similar in certain respects to that shown in Fig. 9.

Figs. 1 and 2 show a trigger switch 20 incorporating the invention mechanically secured within the handle of a suitable device 21 such as va portable electric drill. Assume that device 21 employs an electric motor (not shown) from which the conductors M1 and M2 extend and that the motor (not shown) is energizable from the conductors L1 and L2 which extend into the handle of the device-and which are appropriately connected to a suitable power source (not shown). Briefly, conductors M2 and L2, inserted into the base of normally open switch 20, are electrically connected to each other through bussing means contained therein. Conductors M1 and L1 are each electrically connected to stationary contacts within switch 20 and when the contacts are bridged upon closure of the switch the motor (not shown) of device 21 is energized.

Referring specifically to Figs. 1, 2, 4, 5, 6 and 8,. switch 20 comprises a one-piece base member 22 which is preferably formed 'by molding from phenolic insulating, material such as Bakelite or other suitable electrical insulating material. Base 22 is provided with chambers 23 and 24, best seen in Fig. 5, which accommodate the contact clips 25 and 26, respectively. Clip member 25, identical to clip 26 (see Fig. 10), is preferably formed by stamping from sheet bronze or other suitable resilient conductive material. The flat upper end portions of the clips 25 and 26 are perforated to accommodate the shanks of the brass drive screws 27 and 28, respectively, which, when forced into suitable openings provided within base 22, secure the clips in their respective chambers. Each clip is in electrical contact with its drive screw and the head of each screw serves as one of the stationary contacts of the switch. If preferred, means of securement other than drive screws may be employed, provided that such other means are suitable as contacts. The midportion of each clip is bowed and the lower or free end of each clip, which terminates in a sharp working edge, is reversely curved as shown. Each clip is suspended or floats within its respective chamber so that space exists betwen the lower portion of the clip and Such space allows for downward travel of the lower portion of clip incidental to force being exerted on a conductor in engagement with the .clip tending to withdraw the conductor from the chamber, as will hereinafter become apparent. Since it is not necessary, prior to the insertion of a conductor,

that portions of the clip bear against the rear wall of the chamber, special shaping or bending of the clip to critical tolerances to accomplish such positioning during assembly is avoided. It is apparent, however, that upon insertion of a conductor, the clip must bear against the rear. wall of the chamber to effect proper engagement of the conductor. The sharp working edge of each clip is in proximity to, but does not touch, the forward wall of the chamber.

Figs. 4, 5, 6 and 8 make clear that the floor of each chamber 23 and 24 is provided with a pair of rectangular access holes 29 and 30, and 31, and, 32, respectively, which open into recesses 33 and 34, respectively, formed in the lower outer surface of base 22. In practice, as is clear from Figs. 1, 6 and 8, the bare end of insulated conductor L1, which may be a solid wire or stranded wire which has been tinned to afford rigidity, is inserted through hole 32 into chamber 24 containing contact clip-26 thus forcing the free end of said clip upward in a direction away from the floor of ,saidchamber and forcing the working edge of said clip away from the forward wall of said chamber. Simultaneously, a portion of the clip is forced against the rear wall of the chamber where it remains as long as the conductor is contained within the chamber. Preferably, conductor L1 is pressed sufficiently far into chamber 24 so that the insulated portion thereof extends into recess 34 thus insuring that no uninsulated portions extend from switch base 22,. Conductor L1 slips between the working edge of clip 26 and the forward wall of chamber 24 and the tendency of said clip, now forced against the rear wall of the chamber, to spring back to normal position effects securemechanical and electrical engagement of said conductor between the working edge and the forward wall. Forces exerted on conductor L1 tending to withdraw it from chamber 24 only serve to make the connection more secure as clip 26 is forced closer to the forward wall of said chamber by its own bias and by the downward pulling action of said conductor on the. working edge of said clip. To disconnect conductor L1 from clip 26, a suitable instrument or tool (not shown), such as a stiff piece of wire or the like, is inserted through hole 31 into chamber 24 to force said clip away from said conductor thus freeing the latter for removal. If preferred, conductor L1- may be inserted through hole 31 and hole 32 may be reserved for the use of the removal tool (not shown).

It is to be understood that conductor M1 is connected to contact clip 25 in the same manner that conductor L1 is connected to clip 26. Conductor M1 may be inserted into chamber 23 through hole 29 or 30, as desired, and the unoccupied opening reserved for the use of the removal tool (not shown). 7

It is apparent that the connecting means hereinbefore described readily accommodates itself to engage wire conductors'of varying diameters. Obviously, openings having shapes and sizes other than that shown may be employed to allow for insertion of conductors of various sizes. If preferred, instead of the separate holes 29 and 30, or 31 and 32, a single access hole or slot (not shown) having an elongated contour and capable of accommodating one or more conductors and the removal tool (not shown) may be employed.

Base 22 is further provided with a chamber 35 adapted to accommodate a bussing clip member 36, best seen in Fig. 9. which, while not electrically connected to any portion of switch 20, serves as a convenient means for electrically connecting conductors L2 and M2 to each other. bronze is provided with a fiat, substantially rectangular, upper end portion and is bowed and reversely curved at its lower or free end in a manner similar to contact clips 25 and 26. In addition, the sharp working edge of clip 36 is provided with an indentation 37 which facilitates the location of the removal tool (not shown) when such tool is employed. Bussing clip 36 is suspended in chamber 35 and is secured therein by an insulating plate 38, preferably formed of molded phenolic insulating material such as Bakelite or similar material, which holds the upper portion of said clip against a shoulder or ledge 39 integrally formed in base 22. The lower or free end of clip 36 is disposed above the floor of chamber 35 and the reverscly curved portion, after the conductors have been inserted, bears on a projection 40 integrally formed on the rear wall of chamber 35. Since, in the embodiment shown, clip 36 is to accommodate at least two conductors, chamber 35 is provided with three rectangular access holes 41, 42 and 43 which open into arecess 44, the purpose of which recess is the same as that of recesses; 33 and 34, formed in the lower outer surface of base 22. Conductors L2 and M2 engage and are disenga'geable from bussing clip 36 in the manner explained in connection with conductor L1 and clip 26. Preferably, conductors tively, or vice-versa, thus reserving center hole 42 for the use of removal tool (not shown), but obviously, other besto arrangements are possible. Thus, openings having shapes and sizes other than those shown may be employed. If preferred, instead of three openings 41., 52 and 43, a single elongated access hole or slot (not shown) capable of accommodating a multiplicity of vari-sized conductors and a removal tool (not shown) may be employed. Clip 36 is pivotable on projection 40 so that the working edge of said clip is biased. tightly against conductors employed therewith even if the diameters of two conductors being employed should differ. For example, if conductor L2 is of small diameter and conductor M2 is of somewhat larger diameter, or vice-versa, both are tightly engaged by clip 36 since the clip adjusts itself by pivoting to'accommodate them.

if preferred, instead of clip 36 a bussing clip like 36a as shown in Fig. 15 may be employed in chamber 35. Clip 36a has a slot 36b dividing its lower end portion whichallows the working edges on either side thereof to move independently to adjust themselves to the size of the particular conductor associated therewith.

if preferred, untinned stranded wire may be employed with the invention if the so-called removal tool (not shown) is utilized to effect the necessary displacement of Bussing clip 36, preferably formed of resilient clips 25, 26 or 36, as the case may be, to permit the insertion of such wire into the respective chambers.

Figs. 1, 2, 3, 4,6 and 8 show a trigger lever member 45, preferably molded from phenolic electrical insulating material such as Bakelite or other suitable molded electrical insulating material, associated with base 22. A portion of trigger 45, which is movable with respect to base 22, bears on the raised edge 46 of the forward end of the base and another portion of the trigger bears on theupper surface of insulator plate 38, as shown in Figs. 6 and 8. Trigger is held in proper relation with re spect to base 22 by the stamped, sheet metal frame 47, which is rigidly affixed to the base by the four tabsl48, 49, 50 and 51 (see Figs. 1, 2 and 4) which bend inwardly into recesses provided in the base and by the coaction of the projections 52 and 53 formed on the sides of the base with cutouts provided in the frame (see Figs. .1, 3 and 5). Figs. 2 and 3 show that frame 47 is bent or shaped on both sides thereof to overlie part of the upper portion of base 22. Frame 47 extends inwardly from the sides of base 22 sufficiently far to cause insulator plate 38 to be trapped in place with respect to base 22. Forward and rearward longitudinal travel of trigger 45 with respect to base 22 and to the frame 47 aflixed thereto is limited by the projections 54 and 55 integrally formed on saidtrig'ger which extend through the slots 56 and 57, respectively, provided in said frame.

Referring to Figs. 6, 7 and 8, it is seen that trigger 45 isjadapted to accommodate a contact carrier member 58 whichis preferably formed from a sheet of fiber insulating material or the like.

The forward and rearward ends of the generally T-shaped carrier 58, which ismovable with respect to trigger 45 and base 22, rest on portions of the lever within slot 59 and the lower or depending portion of the carrier extends downwardly through an opening 60 formed in the lever.

i open or off and trigger lever 45 is biased outwardly of frame 47 by the compression spring member 65 interposed between the lever and the upwardly bent tab 66 forming part of the frame, outward travel beinglimited by projections 54' and 55. Carrier 58 is maintained in the position shown in Fig. 6 with respect to lever 45, base 22" and framev 47 by the action of spring member 64 which forces a ball detent 67, part of which is engaged-by the" slot wherein the spring isdisposed, upward: into a for- I, wardly disposed, circular opening 68 provided in the frame.-

conductive, metallic, contact bridge member 69, best seen in Fig. 11, is disposed in'a cutout provided in the depending portion of carrier 58 and is held secure therein by compression spring member '70 which forces the bridge against an insulator plate 71, preferably formed of suitable phenolic electrical insulating material such as Bakelite or the like, which serves as a bearing surface for the bridge.

Fig.5, showing both insulator plates 38 and 71 re- .mov'ed from base 22, indicates the manner in which plate wardly, contact carrier 58 remains poised in the position shown in Fig. 6. As lever 45 is mover further, the forward wall of recess 61 in said lever engages actuator spring member 63 causing the forward end thereof to move away from the forward end of the slot in carrier 58 wherein it is disposed and causing said spring to compress. When lever 45 has moved rearward sufficiently,

.the forward wall of recess 62 pushes against ball detent .67 and forces it out of opening 68 wherein it is normally biased by spring 64. Carrier 58 is now free to move with respect to base 22, frame 47 and lever 45. Spring 63 compressed between lever 45 and carrier 58 tends to resume its normal shape and in doing so thrusts the carrier rapidly rearward in the direction of travel of lever .45. Contact bridge 69 is moved along insulator plate 71 v and up onto stationary contacts 27 and 28, such movement being facilitated by the upturned edges of said bridging contact, thus completing the electrical connection between conductors L1 and M1 and effecting energization of the motor (not shown) of device 21. Further rearward travel of carrier 58 is stopped as ball detent 67 engages rearwardly disposed opening 72 provided in frame 47, while further rearward travel of lever .45 is prevented by the coaction of projections 54 and 55 of said lever with frame 47. It is to be noted that the surfaces of stationary contacts 27 and 28 are somewhat higher than the surface of insulator plate 71 thus insuring that bridge contact 69 is biased firmly against said contacts by spring 70.

Comparison of Figs. 6 and 8 makes clear that with switch in the closed or on position, carrier 58 and the actuator spring 63 carried thereby are in the same position with respect to trigger lever 45 as they are in the open" .position. Carrier 58 and the bridge contact 69 carried thereby are maintained in the closed position with relock-pin 74. A flanged inner end of pin 74 (not'visible) engages and binds against the side of a recess 75 formed in the side of lever 45 when pin 74 is depressed while the lever is maintained in closed position and inward pressure on lever 45 is relieved. To disengage lock-pin 74, lever 45 is moved inwardly a small amount to permit a spring (not shown) within bushing 73 to bias the pin outward.

If preferred, and if the nature of the device employing switch 20 permits, instead of the above-described locking means, other means .(not shown) such as a movable pin-associated with said device, may be'inserted into an opening 76 near the forward end of lever 45 in such a manner as to restrain said lever from being returned to the normally off position. To open switch 20, lever 45 is released and return spring forces it forward'out of frame 47. Contact carrier 58 remains poised in the position shown in Fig. 8. As lever 45 is moved further, the rearward wallof recess dl-engages spring 63 causing the end thereof to move '84 and'85 to prevent displacement of said switch.

away from the rearward end of the slot wherein said spring is disposed and causing it to compress. When lever 45 has moved forwardly sufficiently,-the rearward wall of recess 62 pushes ball detent 67 out of opening 72 wherein is is biased by spring 64. Carrier 58 is again free to move with respect to base 22, frame 47 and lever 45. Spring 63 compressed between lever 45 and carrier 58 tends toresume its normal shape and in doing so thrusts the carrier rapidly forward in the direction of travel of lever 45. Contact bridge 69 moves off of contacts 27 and 28, thus interrupting the connection therebetween, onto insulator plate 71. Forward travel of carrier 58 is stopped as ball detent 67 engages opening 68, and forward travel of lever 45 is limited by projections 54 and 55. All members of switch 20 assume the position shown in Fig. 6.

Switch 20 is susceptible of various modifications, some of which will now be described.

Figs. 12 and 13 show a base member 77 which may be employed with switch 20 instead of base 22. Base 77 may be secured to frame 47 in exactly the same manner as base 22. It is apparent, however, that base 77 is provided with a tapped opening 78 which enables switch 20, when employing such base, to be secured within a suitable device (not shown) in a manner other than that shown in Figs. 1 and 2. Base 77 is not provided with bussing means and it is apparent that the chambers 79 and 80 which areadapted to carry contact clips are disposed within base 77 in a location other than that shown in connection with base 22. Furthermore, base 77 is not provided with an insulator plate such as 71 since contact bridge 69 is to bear on the shoulders '81 and 82 integrally formed within the base.

Fig. l4 shows a frame member 83 which may be employed with'bases 22 or 77. Frame 83 is similar in all respects to frame 47, except that frame 83 is not shown as having a side-lock means and is provided with the bosses 84 and 85. Both such modifications enable a switch employing frame 83 to be mechanically secured in a device having no provision for the extending side-lock and one in which means are provided to engage the bosses If preferred, a side-lock may be employed with frame 83 if the nature of the device employing the switch permits.

Obviously, trigger lever 45 may be provided with a gripping portion having a form or shape other than that shown.

In the operational description of the switch embodiment-shown in Figs. 1, 2, 3, 4, 6 and 8 it was shown that ball detent 67 was dislodged from openings 68 and 72 by trigger lever 45 directly. Obviously, mechanisms employing the invention may provide for other means of positive ball detent displacement. Thus, actuator spring member 63 may be disposed with respect to carrier 58 and lever 45 in such 'a manner that movement of lever 45 in forward or reverse direction causes compression of spring 63 to its solid height. In the latter event, con tinued travel of lever 45 causes movement of carrier 58 which, in turn, causes ball detent 67 to be dislodged by the carrier. Thereafter, the tendency of spring 63 to resume its normal disposition completes the forward or rearward operation of the mechanism in the manner already described. As another alternative method of ball detent dislodgment spring 63 may be selected so that upon a predetermined amount of compression it exerts a force against carrier 58 tending to move it in the direc-, tion of travel of level- 45 greater than the force exerted by spring 64 tending to maintain the carrier in fixed position. After such dislodgment, switch operation would be as already described.

to economical mass production. Modified tor-ms of the switch susceptible of various applications are possible merely by assembling certain of said elements in difierent combinations. Many of the elements are quickly assembled without the air of screws or other fastening devices. The assembled switch unit is conveniently associated with an appropriate device both mechanically and electrically. The novel press-in lead construction employed enables rapid, economical and positive attachment of conductors and permits convenient detachment thereof. The incorporation of bussing connections within the switch eliminates the necessity for a separate external connection. The materials employed and their arrangement and disposition with respect to each other insure that no exposed portions of the switch unit can be electrically charged. The manner in which electrical contact i'sestablished, maintained, and interrupted results in rapid and positive switch operation and prolonged life for the constituent elements of said switch.

I claim:

1. In an electric switch, in combination, an insulator base, a plurality of stationary contacts mounted on said base, a movable member biased in a normal position with respect to said base, a bridging contact, a movable insulator member carrying said bridging contact, said insulator member being normally biased in a given fixed position with respect to said base, and resilient means associated with said insulator member, said resilient means operable upon movement of said movable member out of its normal position after the latter forces said insulator member out of said given fixed position to effect movement of said insulator member into another fixed position thereby effecting engagement of said bridging contact with said stationary contacts, and said resilient means furtheroperable upon biasing of said movable member toward its normal position after the latter forces said insulator them"- her out of said other fixed position to effect disengagement of said bridging contact and said stationary contacts and return of said insulator member into its given fixed position. 7

2. In an electric switch, in combination, an inslilator base, a plurality of stationary contacts mounted on said base, a frame member rigidly secured to said base, a movable trigger member associated with said base by said frame, the forward and rearward travel of said trigge'r member limited by said frame, biasing means disposed between said trigger member ;and said frame to bias said trigger in the forward position, a bridging contact, insulator means for carrying said bridging" contact, said insulator means movable with respect to said base, to said frame and to said trigger, biasing means disposed between said frame and said insulator means to maintain said insulator means in a given position, and resilient means associated with said insulator means and said trigger member, said resilient means operable upon rearward movement of said trigger member to" effect movement of said insulator means from said given position into another fixed position thereby effecting engagement of said bridging contact with said stationary contacts, and said resilient means further operable upon forward movement of said trigger member to effect return of said insulator means to said given position thereby effecting disengagement or said bridging contact and said stationary contacts. I

3. The combination according to claim 2" wherein said resilient means is a spring which eifects' movement of said insulator means when said spring is compressed sufficiently to exert a force greater" than that exerted by said biasing means disposed between said frame and said insulator means.

4. In an electric switch, in combination, an insulator base, a plurality of stationary contacts mounted on said base, a frame member rigidly secured to said base, a

movabletrigger member associated with said base-by said frame, the fcrwar'd and rearward travel of said trigget member limited by said frame, biasing means disposed between'said trigger member and said frame to bias said trigger in the forward position, a bridging contact, insulator means for carrying said bridging contact, said insulator means movable with respect to said base, to said frame and to said trigger, biasing means dis posed between said frame and said insulator means to maintain said insulator means in a given fixed position, and resilient means associated with said insulator means and said trigger member, said resilient means operable upon rearward movement of said trigger member after the latter forces said insulator means out of said given fixed position to effect movement of said insulator means into another fixed position thereby effecting engagement of said bridging contact with said stationary contacts, and said resilient means further operable upon forward movement of said trigger member after the latter forces said insulator means out of said other fixed position to effect return of said insulator means to said, given fixed position thereby effecting disengagement of said bridging contact and said stationary contacts. 7

5. The csmbinanea according to claim 4 comprising means to lock said fixed and bridging contacts in engagemem.

6. In an electric switch, in combination, an insulator base, a plurality of stationary contacts mounted ori said base, a frame member rigidly secured to said base, a trigger member slidably associated with said base by said frame,- the forward and rearward travel of said trigger member with respect to said base limited by said frame, biasing means disposed between said frame and said trigger member tobias the latter in a forward position, carrier means supported by and extending through said trig er member, said carrier means movable with respect to said trigger member, to saidbase and to said name, a bridging contact carried by said carrier means, biasing means disposed between said frame and said carrier to maintainthe latter in a given fixed position, and resilient means mounted on said carrier means, said resilient means disposed with respect to said trigger member so as to be compressible thereby to effect, upon rearward travel of said trigger member which forces said carrier out of said given fixed position, movement of said carrier member into another fixed position thereby causing, engagement of said bridging contact and said stationary contacts, and said resilient means reversely compressible to effect, upon forward travel of said trigger member which forces said carrier out of said other fixed position, movement of said carrier member back to its given fixed position thereby causing disengagement of said bridging contact and said stationary contacts.

7. In an electric switch, in combination, an insulating base, stationary contact means" mounted on said base, a movable operating member having a normal position with respect to said base and being movable from said normal position to another position, movable contact means normally latched in a given fixed position with respect to said base and being movable therefrom into another fixed position into which it is latched, said operating member having means for unlatching said movable contact means, and compressible means operable in response to movement of said operating-member fromits normal position toward said other position following unlatc'hin'g of said movable contact means to efiect snap action movement of said movable tanner means from said given fixed position toward said other fixed position wherein said movable contact means and said stationary contact means are engaged, and said compressible means being further operable in response to movement of said operating member from said other position toward its normal position following unlatching of said movable contact means to effect snap action movement of said movable contact means from said other fixed position toward said given fixed position thereby to efiect 9 10 disengagement of said movable and said stationary con- References Cited in the file of this patent means- UNITED STATES PATENTS 8. The com'bmation according to claim 7 mcludmg 36 7 1 D d t 1 D 14 1943 means for biasing said movable operating member into 23 2 ermon e said normal position with respect to said base. 5 2448'444 Krieger 1948 

